The most recent "State of Server Technology" report found that data centers are still dominated by 2U (81%) and 1U (78%) platforms--those numbers are just slight drops from the 2010 numbers of 83% and 78%, respectively.
The only increases were found in the use of 8U boxes, which was cited by 37% of respondents in 2010 and 38% in 2011, and mini-towers, which had exactly the same numbers. Modular and micro platforms, which came in at 20%, weren't tallied in 2010.
"Despite all the vendor hype around the efficiency of blade servers and their suitability for converged, virtualized I/O fabrics, blade use hasn't grown among our respondents as we would have expected," wrote author Kurt Marko in the most recent report. He cited fears of vendor and platform lock-in as a potential factor in the lack of growth.